Apparatus, system and method for mixing and dispensing dental impression materials

ABSTRACT

An apparatus, system and method for mixing and dispensing dental impression materials is described. A dental impression material mixing machine comprises a water dispenser fluidly coupled to a hollow mixing axle, the mixing axle extending through a pulley, wherein an inner circumference of the hollow mixing axle forms a water conduit and an outer circumference of the hollow mixing axle forms a hub connector, a closeable valve inserted at a water entrance to the water conduit and electronically coupled to a water pump, an electronically commutated motor rotateably coupled to the pulley, wherein the hub connector receives a tubular rotatable hub of a disposable mixing vessel comprising dry dental impression powder, and wherein water is dispensed from the water dispenser into the disposable mixing vessel through the water conduit and hub orifice.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. application Ser. No.14/639,839 to Overton filed Mar. 5, 2015 and entitled “APPARATUS, SYSTEMAND METHOD FOR MIXING AND DISPENSING DENTAL IMPRESSION MATERIALS, whichis a continuation of U.S. application Ser. No. 14/522,149 to Overtonfiled Oct. 23, 2014 and entitled “APPARATUS, SYSTEM AND METHOD FORMIXING AND DISPENSING DENTAL IMPRESSION MATERIALS,” now U.S. Pat. No.9,010,993, which is a continuation-in-part of U.S. application Ser. No.12/823,152 to Overton et al. filed Jun. 25, 2010 and entitled “METHODAND APPARATUS FOR PREPARING AND DISPENSING DENTAL ALGINATE COMPOUND”,each of which are hereby incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the invention described herein pertain to the field ofviscous, thixotropic impression materials. More particularly, but not byway of limitation, one or more embodiments of the invention enable anapparatus, system and method for mixing and dispensing dental impressionmaterials.

2. Description of the Related Art

During the practice of dentistry or orthodontics, it becomes necessaryfrom time to time to take an impression of a patient's teeth in order toprovide treatment or to complete a required procedure, such as filling acavity or fitting a retainer. Conventionally, creating an oralimpression is a two step process, which occurs in a dentist ororthodontist's office. First, an impression or negative mold of thepatient's teeth is created. To create the mold, a viscous, thixotropicimpression material, typically sodium alginate, is prepared by measuringa powder (e.g., alginate powder), and then mixing the powder with aprecise quantity of water in an open container or bowl using a paddle orspatula. The impression material is mixed until smooth and even inconsistency, forming a paste, after which it is put into a dentalimpression tray and placed in the patient's mouth. After a short periodof time, the impression compound sets and becomes firm. Upon removalfrom the patient's mouth, an impression of the patient's dentalarrangement is left in the tray.

The next step is to create a cast from the mold. A plaster derivative,such as dental stone, is prepared, again by measuring out and mixing adry powder with a precise quantity of water to form a paste. The pasteis mixed with a spatula in a bowl, and is then scooped into the dentalimpression mold to cast a mock-up of the patient's dental arrangement(teeth) once the paste dries. From this model, the dentist ororthodontist may plan treatment procedures, or make dental appliancessuitable for the specific patient's dental arrangement.

Currently, the measuring and mixing required to prepare the impressionmaterials is a tedious, messy and cumbersome manual process. Quantitiesof dry powder and water must be carefully measured, the wetted powdersmust be thoroughly and evenly mixed by hand, and once mixed, scooped andtransferred into the impression tray. In a typical alginate impression,1-2 ounces of water and about 2 ounces of powder must be carefullycombined and then spatulated aggressively to reach a creamy consistency.The whole process must be completed quickly and with considerable force.For example, if the process is not completed quickly enough, thecompound may prematurely set. If enough force is not used, the mixturemay not reach the necessary smooth and creamy consistency.

There are a number of difficulties with this common method of dentalimpression preparation. One problem is the consistency and uniformityrequired of the impression compound mixtures. The ratio of water topowder is required to be precise, and this precision is dependent on thecomplete incorporation of water into the powder. If some of the powderis un-wetted and unmixed due to being in inaccessible places in themixing cup or poor mixing technique, the ratio of water to powder iseffectively too high, and the compound will not perform properly. Areasof unmixed powder may also clump and not flow properly.

The impression compound is also sensitive to the formation andentrapment of bubbles, which bubbles negatively affect the smoothness ofthe resulting molds and casts. In addition, the impression powder isprone to “slumping”. This causes a disparity between the required amountand the actual dispensed amount, which discrepancy can be as high as30%.

Another problem is that the impression and dental stone compoundsconsist of a fine powder before being mixed with water. This powderbecomes air-borne during the preparation process, and can be irritatingif inhaled. Additionally, the powder can get into instruments andequipment in the dental office, some of which are quite expensive andintolerant to this type of contamination.

A further problem is the sterility and cleanliness of the equipment usedto mix the compounds. Every item going into the patient's mouth duringdental and orthodontic procedures must be sterilized, usually by use ofan autoclave, a type of oven that applies heat, which kills any harmfulmicro-organisms that may reside on the instruments or appliances beingsterilized. The paddles, bowls and other equipment currently used toprepare impression compound are not able to withstand the heat of theautoclave procedure, and are therefore difficult to sterilize.

Yet another problem arises once the impression material or plasterderivative is mixed and must be transferred to the impression tray. Itis difficult to efficiently transfer the compound without leaving muchof it behind in the mixing cup. Once the impression process is complete,a sticky mess is left behind with many bowls, spatulas and/or spoons todisinfect.

Currently, polyvinyl siloxane is sometimes used as a mold material,rather than sodium alginate, in an attempt to address some of theproblems associated with the preparation of dental impression materials.Polyvinyl siloxane is an elastomeric epoxy that results from combiningtwo viscous liquids, rather than mixing dry powder with water. Theseviscous liquids are sometimes dispensed with a squeeze gun. However,polyvinyl siloxane is between ten and twenty times the cost of sodiumalginate, and is therefore often cost prohibitive. In addition, even ifpolyvinyl siloxane is used as the impression compound, the dental stonefor the cast must still be mixed with water from a dry powder in theaforementioned manner.

Thus, mixing and dispensing dental impression materials usingconventional systems and methods suffers from a large number ofshortcomings. Therefore, there is a need for an apparatus, system andmethod for mixing and dispensing dental impression materials.

BRIEF SUMMARY OF THE INVENTION

An apparatus, system and method for mixing and dispensing dentalimpression materials is described. An illustrative embodiment of adental impression material mixing vessel comprises a disposablevacuum-formed receptacle comprising a flexible tubular wall having agroove circumferentially about a top side of the flexible tubular wall,and a rounded bowl contiguous with the flexible tubular wall and forminga bottom of the disposable vacuum-formed receptacle, the rounded bowlhaving a slit at a base and comprising a removable adhesive sealedlyenclosing the slit, a rigid rim inset in the groove, and a mixingassembly comprising a lid sealedly inserted into the rigid rim, whereina portion of the flexible tubular wall is foldedly sandwiched between aninner diameter of the rigid rim and an outer diameter of the sealedlyinserted lid, and wherein the lid comprises a central round opening, atubular rotatable hub fit into the central round opening and extendingpartially inside and partially outside the disposable vacuum-formedreceptacle, wherein a portion of the rotatable tubular hub extendinginside the disposable vacuum-formed receptacle has a series of aperturesspaced circumferentially and evenly about the tubular hub, and aflexible cord threaded through opposing apertures to form at least twoloops of the flexible cord, the at least two loops extending from thetubular hub contouredly along an inner surface of the flexible tubularwall and rounded bowl, wherein the at least two loops cross each otherat the base. In some embodiments, the disposable vacuum-formedreceptacle further comprises a pre-measured amount of dry dentalimpression powder. In certain embodiments, the dry dental impressionpowder is one of alginate powder or dental stone powder. In someembodiments, there are two loops of flexible cord set at ninety degreesfrom one another. In certain embodiments, the at least two loops sweepabout the inner surface of the flexible tubular wall and rounded bowl asthe tubular rotatable hub rotates, the loop rotation mixes a dry dentalimpression powder inside the disposable vacuum-formed receptacle withwater that enters the disposable vacuum-formed receptacle through thetubular rotatable hub to form dental impression paste and the disposablevacuum-formed receptacle is collapsible and the dental impression pasteis dispensed through the slit to a dental tray as the receptacle iscollapsed.

An illustrative embodiment of a dental impression material mixingmachine comprises a water dispenser fluidly coupled to a hollow mixingaxle, the hollow mixing axle extending centrally through a pulley, thewater dispenser comprising a water pump inside the water dispenser, themixing axle rotatable by the pulley in both a clockwise andcounterclockwise direction, wherein an inner circumference of the hollowmixing axle forms a water conduit, and wherein an outer circumference ofthe hollow mixing axle forms a hub connector, a platform at leastpartially surrounding the hollow mixing axle, the platform comprising aprotuberance that mates to a depression on a lid of a disposable mixingvessel, a closeable valve inserted at a water entrance to the waterconduit and electronically coupled to the water pump, and anelectronically commutated motor rotateably coupled to the pulley,wherein the hub connector receives a tubular rotatable hub of thedisposable mixing vessel, the disposable mixing vessel comprising drydental impression powder, the tubular rotatable hub extending through acentral opening of the lid, and wherein water is dispensed from thewater dispenser into the disposable mixing vessel through the waterconduit and the tubular rotatable hub. In some embodiments, thecloseable valve is one of a solenoid-operated valve or a vacuum-actuatedvalve.

An illustrative embodiment of a method for mixing and dispensing dentalimpression material comprises attaching a disposable mixing vessel to amixing machine, the disposable mixing vessel comprising a pre-measuredamount of dry alginate powder, entering into the mixing machine aquantity of water to be mixed with the dry alginate powder by the mixingmachine, activating the mixing machine to dispense the quantity of waterinto the disposable mixing vessel and mix the quantity of water with thedry alginate powder to form a paste, removing an adhesive from a slit inthe disposable mixing vessel, compressing the disposable mixing vesselto dispense the paste from the slit in the disposable mixing vessel, anddiscarding the disposable mixing vessel. In some embodiments, the methodfurther comprises attaching a second disposable mixing vessel to themixing machine, the second disposable mixing vessel comprising apre-measured amount of dry dental stone powder, entering into the mixingmachine a second quantity of water to be mixed with the dry dental stonepowder by the mixing machine, activating the mixing machine to dispensethe second quantity of water into the second disposable mixing vesseland mix the second quantity of water with the dry dental stone powder toform a second paste, removing an adhesive from a second slit in thesecond disposable mixing vessel, compressing the second disposablemixing vessel to dispense the second paste from the second slit in thesecond disposable mixing vessel, and discarding the second disposablemixing vessel.

In further embodiments, features from specific embodiments may becombined with features from other embodiments. For example, featuresfrom one embodiment may be combined with features from any of the otherembodiments. In further embodiments, additional features may be added tothe specific embodiments described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the inventionwill be more apparent from the following more particular descriptionthereof, presented in conjunction with the following drawings wherein:

FIG. 1A is a perspective view of a mixing vessel of an illustrativeembodiment with the lid open.

FIG. 1B is a perspective view of a mixing vessel of an illustrativeembodiment with the lid closed.

FIG. 2 is a perspective view of a whisk of an illustrative embodiment.

FIG. 3 is a perspective view, with part broken away, of a mixing machineof an illustrative embodiment.

FIG. 4 is a cross sectional view across line 4-4 of FIG. 3 of a mixingmachine of an illustrative embodiment.

FIG. 5 is a plan view from below of a mixing axle of an illustrativeembodiment.

FIG. 6 is a flowchart of a method of mixing and dispensing dentalimpression material of an illustrative embodiment.

FIG. 7 is a perspective view of a mixing vessel of an illustrativeembodiment during dispensation of mixed paste.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and may herein be described in detail. Thedrawings may not be to scale. It should be understood, however, that thedrawings and detailed description thereto are not intended to limit theinvention to the particular form disclosed, but on the contrary, theintention is to cover all modifications, equivalents and alternativesfalling within the spirit and scope of the present invention as definedby the appended claims.

DETAILED DESCRIPTION

An apparatus, system and method for mixing and dispensing dentalimpression materials will now be described. In the following exemplarydescription, numerous specific details are set forth in order to providea more thorough understanding of embodiments of the invention. It willbe apparent, however, to an artisan of ordinary skill that the presentinvention may be practiced without incorporating all aspects of thespecific details described herein. In other instances, specificfeatures, quantities, or measurements well known to those of ordinaryskill in the art have not been described in detail so as not to obscurethe invention. Readers should note that although examples of theinvention are set forth herein, the claims, and the full scope of anyequivalents, are what define the metes and bounds of the invention.

As used in this specification and the appended claims, the singularforms “a”, “an” and “the” include plural referents unless the contextclearly dictates otherwise. Thus, for example, reference to a flexiblecord may also refer to multiple flexible cords.

As used in this specification and the appended claims, the term “dentalimpression material” refers to thixotropic impression materials such assodium alginate, as well as to plaster derivatives such as dental stone,used in creating casts and/or molds for dental arrangements.

One or more embodiments provide a system for mixing and dispensingthixotropic materials. While so as not to obscure the invention, theinvention is described herein in terms of a dental and/or orthodonticembodiment, nothing herein is intended to limit the invention to thatembodiment. Any thixotropic or similar material that must be measured asa dry powder and expediently mixed with precise quantities of water oranother liquid to produce a smooth paste, for example medical epoxies,fillers used in surgery and/or dehydrated foods, may benefit from theapparatus, system and method of illustrative embodiments. In addition,alginate impressions may be used for purposes other than dentalpurposes, such as arts and crafts.

Illustrative embodiments provide a consistent, clean and sterile systemfor preparing dental impressions and casts. Illustrative embodiments mayensure complete mixing of dry dental impression materials with water,minimizing bubbles and resulting in a paste of a predictable smooth andcreamy consistency. Dry powder need not be measured by the operator, noris it exposed to other equipment in the dental or orthodontist office.Using illustrative embodiments, no mixing containers or utensils requirecleaning or sterilization. The mixing vessel may be disposable, and lowcost such that it may be discarded without financial concern. Forexample, in some embodiments a disposable mixing vessel may be abouttwice the cost of dry alginate powder, which is currently about $0.60,the use of the disposable mixing vessel removing the cost of clean-upand disinfection, currently estimated at about $1.00-$2.00.

In an illustrative embodiment a disposable, flexible vessel including aresilient whisk may be pre-filled with a measured amount of dry powderto be used in creating a dental impression or cast. The vessel mayattach to a water-dispensing axle on a discrete mixing machine, whichmay be small and light enough to sit on a counter in a dental officeand/or be portable. The operator may select a quantity of water to bedispensed and mixed with the dry powder by the mixing machine. Thequantity of water may, for example, be selected based upon the type ofpowder used and/or the preferred thickness of the resulting paste. Thewater-dispensing axle operates to rotate a hub of the mixing vesselwhisk that conforms to the shape of the vessel, and uniformly mixes thedry powder with the water until the dental impression material hasreached its desired consistency. Once the paste is ready, the disposablevessel may be removed from the machine, and the paste dispensed from thevessel by applying pressure, for example by folding, compressing and/orsqueezing the vessel. Adhesive over a slit in the vessel may be removedby the operator to allow the paste to exit the vessel and be placed in adental tray or mold. The empty vessel may then be discarded, leavinglittle waste, and only the dental tray to be cleaned and sterilized, oralternatively also discarded, improving the speed and ease of clean up.

Disposable Vessels

A flexible, disposable mixing vessel may be employed in the system andmethod of illustrative embodiments. The mixing vessel may include aspecific, pre-measured amount of dry dental impression material, forexample 1.5 ounces, 2.0 ounces or 2.5 ounces of dry powder. Themeasured, dry powder may be sealed and/or contained in the vessel uponreceipt by the operator, and need not be measured or poured by theoperator. FIG. 1A and FIG. 1B illustrate an exemplary mixing vessel. Asshown in FIGS. 1A and 1B, mixing vessel 100 includes a receptacle 105.Receptacle 105 maybe spherical and/or cylindrical in shape. In someembodiments, wall 110 may be cylindrical and/or tubular in shape andbowl 115 may be contiguous with wall 110 and rounded and/or spherical inshape. Receptacle 105 may be hollow to accommodate dry powder, water andmixing equipment, and open at a top side to accommodate lid 120.Receptacle 105 may be comprised of a thermoplastic and/or vacuum-formingmaterial such as ethylene-vinyl acetate copolymer, also known as “softEVA”, low density polyethylene (LDPE) or other material having similarproperties. Receptacle 100 may be 1 mm, 1.5 mm 2 mm, 3 mm thick oranother similar thickness and be flexible and/or collapsible. In someembodiments, receptacle 105 may be transparent such that the dry powderand mixing equipment is visible to an operator during the mixingprocess. In certain embodiments, receptacle 105 may be trimmed andformed from a 5 inch by 5 inch square of 1 mm thick soft EVA.

Upper side of wall 110 may include groove 125 extendingcircumferentially about the rim of wall 110 just below the top edge.Retainer ring 130 may be inserted into groove 125 and assist insupporting receptacle 100. Retainer ring 130 may include acircumferential indentation 135 on its inner diameter such thatindentation 135 may receive lid 120.

Receptacle 100 may be closed with lid 120. FIG. 1A illustrates anexemplary embodiment of lid 120 open, and FIG. 1B illustrates anexemplary embodiment of lid 120 closed. Lid 120 may be a flat, rounddisk that may snap, thread, twist, press and/or fit tightly intoretainer ring 130 and/or indentation 135. Lid 120 may snap intoindentation 135 on the inside of retainer ring 130. Receptacle 105material may fold and/or sandwich in between the outer diameter of lid120 and the inner diameter of retainer ring 120 such that it is pinchedby the snapping of lid 120 into retainer ring 130. Pinching a portion ofreceptacle 105 between lid 120 and retainer ring 130 may serve to keepreceptacle 105 from slipping off of retainer ring 130 and/or to providean extra sealing mechanism. The connection between retainer ring 130 andlid 120 may be a firm connection that requires considerable pressure topress the receptacle 100 material between retainer ring 130 and lid 120in order to form a tight seal. Receptacle 100 may include slit 160 fordischarge of mixed paste. Slit 160 may be a hole, slit or other aperturethat is covered with adhesive 140. Slit 160 may be at the bottom (base)of bowl 115 or at another location of bowl 115 or wall 110. Placing slit160 at the bottom, center of bowl 115 may provide for more efficientdispensation of mixed paste. Adhesive 140 may be removable and keepreceptacle 105 sealed closed until the mixed paste is ready to bedispensed.

Lid 120 may be a flat, round disk and include one or more depressions145 on its outer surface for securing, attaching and/or fastening mixingvessel 100 onto a mixing machine. When lid 120 is closed onto receptacle105, lid 120 may removeably lock into a protuberance on a mixing machineas shown in FIG. 4, such that mixing vessel may be attached or removedfrom the mixing machine as necessary. Lid 120 may include a centralopening 165 for receipt of hub 150. The outer circumference of lid 120may include recess 155 for threading, snapping and/or mating withindentation 135 on retainer ring 130. When inserted into central opening165, hub 150 may partially extend inside receptacle 105, inside of lid120, and partially outside of receptacle 105, outside of lid 120.

Hub 150 may be flanged at flange 205 so as to press up against the innerside of lid 120 when positioned within closed lid 120. Hub 150 may alsoinclude orifice 210 that may function as a water delivery port for thedelivery of water into receptacle 105 and/or may mate with an axle of amixing machine. Flange 205 and/or hub 150 may include apertures 215evenly and circumferentially spaced about the side of hub 150 inside ofreceptacle 105. As shown in FIG. 2, apertures 215 may allow for cords170 to be threaded onto hub 150 to form whisk 220. In some embodiments,four apertures 215 may be evenly spaced about flange 205 to accommodatetwo cords 170. Each cord 170 may form a loop inside receptacle 105, witheach loop making use of two opposing apertures 215. Cords may be sizedsuch that they contour along wall 110 and bowl 115. Cords 170 may crossat the base of bowl 115 and be arranged perpendicularly such that cords170 are set ninety degrees from one another, as illustrated in FIG. 2.In other embodiments, three cords 170 may be spaced sixty degrees fromone another. In some embodiments only one cord 170, or more than threecords may be used to form the whisk 220.

Referring to FIG. 2, cords 170 and hub 150 may form a whisk 220 thatspins inside receptacle 105, with cords 170 sweeping along wall 110 andbowl 115. Cords 170 may be made of a flexible, resilient plastic or anelastic, synthetic polymer such as nylon, that exerts an upward force onhub 150 and a downward force on bowl 115, bowing at the sides and alongwall 110 such that the when hub 105 rotates, cords 170 sweep across theentire inner surface of wall 110 and bowl 115 of receptacle 105. Cordsmay be made of nylon trimmer line, such as 0.080 diameter round trimmerline.

The materials used for mixing vessel 100, including receptacle 105,cords 170, lid 120, hub 150 and/or retainer ring 130 may be inexpensivenylon or plastic polymers, including polypropylene, acrylonitrilebutadiene styrene (ABS), LDPE, high-density polyethylene (HDPE), and/orEVA. The total volume of plastic necessary for each mixing vessel 100may be comparable to the amount of plastic in a cup of yogurt.

Mixing Machine

A mixing machine may be used to dispense water into mixing vessel 100and rotate whisk 220. FIG. 3 is an illustrative embodiment of a mixingmachine. In some embodiments, mixing machine 300 may be lightweight,such as between about 1 and 5 pounds, and be about 11 inches in heightand 10 inches in width and/or about the size of a small blender orcoffee maker. Mixing machine 300 may operate off of alternative currentor direct current. In the case of alternating current, mixing machine300 may include a cord (not shown) to plug into a wall outlet. In thecase of direct current, mixing machine 300 may be configured to operateoff of batteries.

Mixing machine 300 may include a mixing vessel 100 receiving and/orattachment area. An exemplary mixing vessel 100 receiving area 400 ofmixing machine 300 is illustrated in FIG. 5. As shown in FIG. 5, mixingvessel 100 receiving area 400 includes a platform 305 with protuberances310. Protuberances 310 may slide into depressions 145 on lid 120 toremoveably lock mixing vessel 100 onto mixing machine 300. For example,a protuberance 310 may slide into a larger area of depression 145, andthen as mixing vessel 100 is rotated lock into a narrower area ofdepression 145 to be held securely in place. To remove mixing vessel 100from platform 305, an operator may rotate mixing vessel 100 in theopposite direction in order to slide protuberances 310 from the narrowerarea of depression 145 and into the wider area where protuberances 310may fall out of depression 145. It may be appreciated that in otherembodiments, lid 120 may include protuberances and platform 305 mayinclude depressions. In yet other embodiments, mixing vessel 100 mayclip, snap, stick or otherwise attach into place, such that it isattached to mixing machine 300 during water dispensing and mixingoperations, but removable upon completion of the water dispensing andmixing operations.

Platform 305 may be in proximity to mixing axle 315, which may behollow. Outer circumference of mixing axle 315 may form hub connector610 and inner circumference of mixing axle 315 may form water conduit605. Platform 305 may surround, partially surround and/or be situatedadjacent to mixing axle 315. Mixing axle 315 may be hollow in order todispense water into mixing vessel 100 through water conduit 605, asshown in FIG. 4. The outer circumference of mixing axle 315 may form hubconnector 610 and be shaped to fit inside of, engage and/or mate withorifice 210 of hub 150. In FIGS. 2 and 5, hub connector 610 and orifice210 are both shown hexagonal in shape, although other polygon orrounded, or lock and key configurations are possible. As shown in FIG.4, when hub 150 is connected to hub connector 610 of mixing axle 315,water stream 410 may be dispensed through water conduit 605 and/or thehollow portion of mixing axle 315, through orifice 210 of hub 150, andinto mixing vessel 100. Also when hub 150 is connected to hub connector610 and lid 120 is attached to platform 305, whisk 220 including hub 150and cords 170 may rotate with mixing axle 315, whilst lid 120 andreceptacle 105 remain stationary. In some embodiments, hub connector 610of mixing axle 315 may be brass. The shape of mixing axle 315 and itshollow interior assist in keeping dispensed water away from electricalcomponents in the system of illustrative embodiments.

As shown in FIG. 4, mixing axle 315 may extend centrally andlongitudinally through pulley 320, such that mixing axle 315 is parallelto the axis of rotation of pulley 320 and pulley 320 extends radiallyabout mixing axle 315. Mixing axle 315 may be secured to pulley 320 androtatable by pulley 320 using belt 615 (shown in FIG. 3), which belt 615may be turned by motor 355.

Illustrative embodiments may provide for a predictable, leak-proofmethod of water delivery into mixing vessel 100. FIG. 4 illustrates anexemplary mixing vessel 100 attached to mixing machine 300 such thatwater stream 410 may be dispensed into mixing vessel 100 by mixingmachine 300, and mixing machine 300 may mix the water with dentalimpression material 415 inside mixing vessel 100. When mixing vessel 100is inserted onto the mounts (protuberances 310), hub 150 may mate withhub connector 610 of mixing axle 315. The hub 150 of the mixing vessel100 may slide about hub connector 610 of mixing axle 315 like a sleeveand engage it at such an orientation that when mixing axle 315 turns,hub 150 also may rotate. Upward pressure imposed by cords 170 onto hub150 may assist in securing the connection between mixing axle 315 andhub 150. With this pressure, hub 150 may be pushed onto the mixing axle315 and held securely in place, which may prevent hub 150 from slidingoff of mixing axle 315. In such embodiments, pumping force from waterpump 330 or a faucet and gravity may contribute to a secure waterdelivery scenario as water flows through hollow mixing axle 315 and/orwater conduit 605 of mixing axle 315. In some embodiments, hub 150 maybe keyed to mixing axle 315 at a keyway (not shown). Mixing vessel 100may receive water without leaking or spillage. The water may passthrough the hollow mixing axle and/or water conduit 605 and into themixing vessel 100 interior without coming back out. The flow, volume andpressure of water, sealing mechanism of lid 120 and retainer ring 130,and/or upward pressure of the cords 170 against the hub 150 all maycontribute to creating barriers to leakage.

Returning to FIG. 3, water may be dispensed by mixing machine 300 fromwater receptacle 325, through flexible tubing 345, and then throughwater conduit 605 of mixing axle 315. Water receptacle 325 may beremovable from mixing machine 300 so as to be easily filled with waterfrom a tap or hose. A small submersible water pump 330, such as a microsubmersible pump driven by a brushless motor may be used to pump waterfrom water receptacle 325 to mixing vessel 100. In some embodiments,tubing 345 may attach to a water hose, faucet or nozzle and waterreceptacle 325 and/or water pump 330 may not be necessary. Dial 335 onmixing machine 300 may allow an operator to control the quantity ofwater that is dispensed into mixing vessel 100. For example, if anoperator desired to mix dental alginate for an adult mouth, he or shemay select 45 mL of water to be dispensed into mixing vessel 100. Forthicker or thinner paste, another type of powder such as dental stone,or a child's mouth for example, another quantity of water may beselected.

In order to dispense the correct amount of water during each usage, avalve 360 may be employed in conjunction with water pump 330. Valve 360may be placed at the entrance of water conduit 605 and may worksynchronously with water pump 330. The water pump 330 and valve 360 maybe controlled by a circuit board (not shown) with a programmed and/orinputted time interval. When the program is activated, for example by apush of switch 340 by the operator, the water pump 330 pushes waterthrough tubing 345 while the valve 360 at the entrance to water conduit605 and/or mixing axle 315 stays open. When the interval ends, the valve360 may close and pump 330 may cease operations, and the water stopsflowing. This cohesive operation of the pump 330 and valve 360 may allowfor predictable water flow forward and a minimum of “suckback” (i.e.,the water stays put in tubing 345 when valve 360 closes). The next watercycle then may start at the same point as the previous cycle and thusdeliver substantially the same amount of water each time and/or deliverthe amount of water selected by the operator, as entered with dial 335.Valve 360 may be a solenoid operated valve, a mechanical valve operatedby a linkage or may be vacuum actuated.

A motor 355 may reside inside case 350 to cause rotation of mixing axle315. Motor 355 may be a brushless motor, an electronically commutatedmotor, an induction motor, a permanent magnet synchronous motor and/oranother type of motor capable of causing rotation in both a clockwiseand counter-clockwise direction. Rotation in two directions may assistin complete, thorough mixing of the dry impression material 415 andwater 410. In instances where whisk 220 turns only in a single directionpooling of the material may occur inside mixing vessel 100. Mixingbi-directionally may assist in combating pooling of material. In certainembodiments, mixing in only a single direction may be necessary. Motor355 may operate to turn pulley 320 using belt 615. Belt 615 may bewrapped about both pulley 320 and motor 355 such that the rotation ofmotor 355 is conveyed to pulley 320. Mixing axle 315 may be fixedlysecured to pulley 320, extending longitudinally through pulley 320 andparallel to pulley 320's axis of rotation.

In some embodiments, a 730 kv rpm motor, with a 5.0 mm shaft, 11.1-14.8volts and no-load current of 1.9 amps at 11.1 volts and 330 maximumwattage may be employed as motor 355. A lower voltage motor may reducethe possibility of electrical shock to the operator. In presentlypreferred embodiments, motor 355 should operate off DC current, becompact, deliver sufficient torque, deliver an acceptable range of RPM's(such as 200-500), be programmed to turn, stop and then turn in theopposite direction, be readily available and be relatively inexpensive.A HobbyKing Donkey ST3508-730 kv brushless motor or similar is asuitable motor.

Directing the water away from the motor also may assist in preventingagainst electrical shock. Case 350 may be at the top of mixing machine300 as illustrated in FIG. 3, or alternatively may be placed at the baseof mixing machine 300. In instances where case 350 is at the top ofmixing machine 300, motor 355 may be placed about 6-8 inches behindmixing axle 315 where water flows. A bridge rectifier may be employedsuch that motor 355 may run off of either AC or DC power as required. Incertain embodiments, motor 355 may be pre-programmed to operate in arotation cycle whereby it automatically alternates rotation directionsonce turned on in mixing mode.

Switch 340 may allow an operator to turn mixing machine 300 on or off,or switch from a water dispensing to a mixing function. Switch 340 mayalso allow an operator to select whether the motor rotates in aclockwise or counter-clockwise direction. In certain embodiments, motor355 may be pre-programmed to operate in a rotation cycle whereby itautomatically alternates the direction of rotation.

Operation of the Mixing Machine

Once mixing vessel 100 is mounted on platform 305, mixing machine 300may be activated by pressing, touching or otherwise activating switch340. Switch 340 may start a pre-set water delivery cycle followed by amixing cycle that is determined by the operator. All dispensing of waterand mixing is done by mixing machine 300. The operator simply pressesswitch 340 to accomplish all of the steps to obtain thoroughly mixeddental impression material. Once the cycle is stopped, the mixing vesselmay be untwisted, slid or otherwise removed from protuberances 310. Theoperator then holds mixing vessel 100 in one hand and removes adhesive160 with the other hand. The paste may then be squeezed out with thegripping hand like paste out of a tube. FIG. 7 illustrates an exemplarymixing vessel 100 as it is being collapsed to dispense mixed paste 700.As shown in FIG. 7, receptacle 105 may collapse when squeezed, but lid120 may not. In some embodiments, dispensing of mixed paste 700 isaccomplished by the operator's palm forcing down the lid 120 to the baseof the bowl 115 in a fashion similar to the action of squeezing a tennisball.

This process may be repeated a first time for dental alginate to createthe paste that will form the dental impression, and then a second timefor the dental stone to create the paste that will form the dental cast.A separate, disposable mixing vessel 100 that contains the correctamount and type of dry powder may be used for each step. An exemplarymethod for mixing and dispensing dental impression material isillustrated in FIG. 6. A user may first attach a disposable mixingvessel 100 to mixing machine 300, the disposable mixing vessel 100comprising a specific, pre-measured amount of dry alginate powder atstep 500. For example, the user may attach protuberances 310 todepressions 145 by lightly pressing and twisting mixing vessel 100 intoplace on platform 305. At step 505, the user may then enter into mixingmachine 300 a quantity of water to be mixed with the dry alginate powderby mixing machine 300, for example by turning dial 335. The user thenactivates the mixing machine 300 to dispense the quantity of water andmix the quantity of water with the dry powder to form a paste, forexample by pressing switch 340 at step 510. Once switch 340 has beenpressed, mixing machine 300 may proceed through a pre-programmed mixingcycle that may alternate direction of rotation. When the machine hasreached the desired consistency, the user may turn switch 340 off atstep 515. A transparent receptacle 105 may assist in allowing the userto view when the paste has reached the correct consistency.Alternatively, the mixing machine 300 may be programmed to stop basedupon pre-programmed timing and step 515 may not be necessary. The usermay then remove mixing vessel 100 from the mixing machine at step 520and remove adhesive 140 from slit 160 in the disposable mixing vessel100 at step 525. The user may then squeeze the disposable mixing vessel100 to dispense the paste from the slit 160 in the disposable mixingvessel 100 and into a dental tray at step 530. This process may berepeated at step 535 if additional paste is needed for the cast. Usedmixing vessels 100 may be discarded at step 540. Used mixing vessel(s)100 may be discarded at any point after the mixed paste has beendispensed from them.

Illustrative embodiments may provide consistent mixing and dispensing ofdental impression material in a fashion that reduces the laborintensiveness of the process as compared to conventional systems andmethods. Using illustrative embodiments, the need for a technician tomeasure and/or handle dry powder may be eliminated. Thorough mixing ofwater with dry powder may be accomplished in an expedient manner with apredictable force and paste consistency, and a reduced risk of bubbles,clumping or slumping. Mixed impression paste may be blended anddispensed in a cost-efficient disposable mixing vessel that mayeliminate the need to clean and/or sterilize mixing cups and utensilsand therefore reduce the manpower otherwise needed to do so.

Thus, the invention described here provides one or more embodiments ofan apparatus, system and method for mixing and dispensing dentalimpression materials. While the invention herein disclosed has beendescribed by means of specific embodiments and applications thereof,numerous modifications and variations could be made thereto by thoseskilled in the art without departing from the scope of the invention setforth in the claims. The foregoing description is therefore consideredin all respects to be illustrative and not restrictive. The scope of theinvention is indicated by the appended claims, and all changes that comewithin the meaning and range of equivalents thereof are intended to beembraced therein.

What is claimed is:
 1. A dental impression material mixing systemcomprising: a mixing vessel comprising: a flexible tubular wall; and arounded bowl contiguous with the flexible tubular wall and forming abottom of the mixing vessel, the rounded bowl having a slit at a baseand comprising a removable adhesive sealedly enclosing the slit; a lidsecured on the flexible tubular wall; a tubular rotatable hub fit intothe lid; a flexible cord threaded through the tubular rotatable hub toform at least two loops of the flexible cord, the at least two loopsextending from the tubular hub contouredly along an inner surface of theflexible tubular wall and rounded bowl, wherein the at least two loopscross each other at the base; and a mixing machine, the mixing machinecomprising a rotatable hub connector and a water conduit; wherein themixing vessel removeabley couples to the mixing machine, and wherein themixing machine operates to dispense water into the mixing vessel androtate the at least two loops of flexible cord such that dry dentalimpression material is hydrated and mixed to form a dental impressionpaste.
 2. The dental impression material mixing system of claim 1,further comprising a platform surrounding the hub connector, wherein theplatform is mateable with a lid of the mixing vessel.
 3. The dentalimpression material mixing system of claim 1, further comprising anadjustable water quantity control configured to adjust an amount ofwater dispensed into the mixing vessel.
 4. The dental impressionmaterial mixing system of claim 1, wherein a premeasured amount of thedry dental impression material is sealed within the mixing vessel.